TB-500 · animal tests and open risks
What TB-500 changed, and what remains unknown
Some animal wounds and hearts healed faster with Thymosin Beta-4. Other work raised cancer concerns. No published trial has checked those shots in people.
What TB-500 changed in wounds and organs
Researchers timed how fast animal wounds closed. They also watched injured hearts and new blood vessels [21].
TB-500 copies one short stretch of Thymosin Beta-4 [1]. Researchers make that copy in a lab.
They number the stretch from 17 through 23. The numbers only name its place in the full protein.
The tests covered wounds, ligaments, hearts, brains, and muscle. Animals and cells grown in dishes were tested.
Here’s the short answer. Some animal wounds closed faster.
Some animals made more tiny blood vessels. Some injured cells lived longer when blood ran low.
Researchers also checked swelling and healed tissue strength. Results differed from test to test.
Researchers haven't published a study of TB-500 shots in people. Self-use wasn't compared in study groups [20].
Thymosin Beta-4 findings can't prove TB-500 is safe. They show what human studies still need to check.
Read the reported TB-500 side effects here. That page keeps Thymosin Beta-4 findings separate.
How Thymosin Beta-4 and TB-500 differ
Thymosin Beta-4 is a protein the body makes. It helps when damaged tissue repairs itself.
Thymosin Beta-4 contains one short stretch, numbered 17 through 23 [1]. TB-500 copies that stretch.
TB-500 and full Thymosin Beta-4 may act differently. In dishes, the copied stretch helped repair cells move.
Thymosin Beta-4 helped old and diabetic mice close wounds and make collagen [2]. Collagen is the strong material that helps hold tissue together.
The Thymosin Beta-4 mouse results don't make the two forms equal. One study gave Thymosin Beta-4 to 54 healthy people [16].
That study found no serious harm. It didn't test TB-500 shots.
Another brief study used Thymosin Beta-4 eye drops [23]. One group got treatment; another got placebo drops without the protein.
Both groups reported problems. More came from the placebo group, but researchers couldn't say why.
Neither human test used TB-500 shots. A Thymosin Beta-4 result may not fit the copied stretch.
The animal research page shows what changed. The TB-500 side effects page names the open risks.
What is TB-500? Three animal findings
Three findings came up more than once. None has been proved in people.
Wounds and ligaments healed faster. Rat wounds closed 42% more by day 4.
By day 7, the change reached 61% [3]. Dish tests found repair cells moved 2–3-fold farther, or twice to three times as far.
A cut rat knee ligament got 1 microgram of Thymosin Beta-4 in surgical glue. A microgram means one part in a million of a gram.
After 4 weeks, the ligament was stronger. Its collagen looked more even [9].
Mouse muscle cells also moved toward hurt spots. Open gaps in those dish tests closed faster [10][11].
Injured hearts and brains lost less function. Rats got 5.37 milligrams of Thymosin Beta-4 for every kilogram of weight.
After 28 days, damaged heart tissue was 43% smaller [6]. Another study used 6–30 milligrams for each kilogram after rat brain injury.
Rats moved and learned better after 30 milligrams per kilogram [7]. Researchers measured both movement and learning.
Swelling and repair cells changed. For 4 weeks, sick mice got 12 milligrams of Thymosin Beta-4 per kilogram each day.
Immune cells that drive swelling became less common. A calming chemical, called IL-10 in the paper, also rose [22].
The mouse livers showed less swelling too. That looked helpful in mice, not proven in people.
Margin note: these tests used animals and cells. They don't tell you what the treatment would do to you.
What human tests haven't settled about cancer and safety
TB-500 can help new blood vessels grow. Tumors also use new vessels for growth.
In mice with skin cancer, extra Thymosin Beta-4 went with more cancer spread. The tumors also grew more blood vessels [12].
Human colon cancer samples raised the same concern. Thymosin Beta-4 appeared where new blood vessels kept growing [13].
Pancreas cancer cells made more Thymosin Beta-4 too. The cancer cells used the protein to help them live [14].
No human Thymosin Beta-4 study shows that added TB-500 causes cancer. No human study has ruled out that harm.
Past cancer makes this gap matter to you. A doctor can weigh it with your own history.
FDA listed TB-500 in Category 2 from October 2023 through February 2024. During that time, safety concerns kept pharmacies from making it for people.
FDA's public page doesn't name who asked for review. The unnamed person or group later withdrew the request.
That ended the review; it wasn't approval or proof of safety. The world sports drug-testing group, WADA, still bars TB-500.
A Canadian athlete got a 4-year ban in a TB-500 case [18]. A 2023 lab check also tested two related products sold online [17].
Some vials didn't hold what their labels promised. A bad vial can harm you before TB-500's own effects begin.